Spray nozzle



June 7, 1955 J. M. PATTERSON 2,710,229

SPRAY NOZZLE Filed May 25. 1950 Inventor JOSEPH Mg PA TTERSO/V.

' Cttorncg United States Patent U SPRAY NOZZLE Joseph M. Patterson,Lansing, Mich., assignor to Food Machinery and Chemical Corporation, SanJose, Calif., a corporation of Delaware Application May 25, 1950, SerialNo. 164,202

4 Claims. (Cl. 299-140) The present invention relates to spray nozzles,and more particularly to a shear type spray nozzle for mounting in anair stream for producing air-borne spray.

An object of the present invention is to provide an improved shearnozzle for mounting in a high velocity air stream.

Another object is to provide a simple and effective device for feedingspray particles into an air blast.

Another object is to provide a spray nozzle wherein spraying liquid issupplied to the nozzle at relatively low pressure through a relativelylarge orifice and the spray particles are created by the shearing actionof a high velocity air blast in which the nozzle is located.

Another object is to provide a shear nozzle for mounting in an airblast, with an end of the nozzle where the shearing action occurs slopedto diverge from the direction of air flow past the nozzle.

Another object is to provide a shear nozzle in which the amount ofliquid fed therethrough can be varied between relatively wide lirnitswithout materially changing the size range of spray particles producedthereby.

These and other objects and advantages of the present invention will beapparent from the following description and the accompanying drawings,wherein:

Fig. 1 is a perspective view of a shear nozzle embodying the inventionmounted on a fragment of manifold pipe, portions being broken away.

Fig. 2 is a section taken along the mid-plane of the nozzle indicated bythe line 22 of Fig. 1.

Fig. 3 is a fragmentary perspective view showing spray nozzles embodyingthe invention mounted at the air blast outlet of a' radial dischargetype of spraying machine.

Fig. 4 is a fragmentary longitudinal section through an air blast tubeof an axial discharge type of spraying machine, with a spray nozzleembodying the invention mounted therein.

The shear nozzle of the present invention is adapted to be mounted inany suitable high velocity air stream, but for the purpose of thepresent specification it will be described as mounted either in the airblast from a radial discharge type of sprayer of the type disclosed inPatent 2,476,960 to George W. Daugherty, issued July 26, 1948, asillustrated in Fig. 3 of the present drawings, or in that from an axialdischarge type of sprayer of the type disclosed in patent application ofGeorge W. Daugherty, Serial No. 28,317, filed May 21, 1948, now PatentNo. 2,667,717, as illustrated in Fig. 4 of the present drawings.

In the embodiment of the invention illustrated in Figs. 1, 2 and 3 acombined nozzle-support and liquid-supply tube has one end thereofscrewed into an adapter bushing 11 which in turn is screwed into a sideoutlet 12 of a liquid supply manifold 13. The assembled length of thetube 10 and bushing 11 should be such as to locate the nozzle in adesired part of the air stream. The manifold 13 is arranged adjacent theair blast outlet 14 (Fig. 3) of a radial discharge sprayer 15 of thetype disclosed in Daugherty Patent 2,476,960 mentioned previouslyherein.

Patented June 7, 1955 Each tube 10 is internally threaded on its freeend, and an orificed fitting 18, with threaded end portions 19 and 20(Fig. 2) and an intermediate nut portion 21 formed integrally therewith,is screwed into the free end of the tube 10. The fitting 18, which maybe considered as part of the nozzle, has a jet orifice 22 therein of apredetermined but relatively large diameter, for example, in the rangebetween three sixty-fourths and one-eighth of an inch. Liquid dischargedthrough this orifice is directed axially of the fitting toward theopposite wall of a nozzle head 23.

The head 23 is tubular, and is herein illustrated as being substantiallycircular in cross sectional shape, although the use of other shapes,such as rectangular, triangular, oval and so-called streamlined section,is contemplated. One or both ends 24 and 25 of the tubular head portionare exposed to the air stream and are sloped to diverge from thedirection of How of the air stream in which the nozzle is mounted. Thehead 23 has a threaded hole 28 therethrough midway of the length of aside thereof, into which is screwed the threadedouter end of the fitting18.

The amount of divergence of the end faces 24 and 25 of the head portion23 from the direction of air flow materially affects the performance ofthe nozzle. For example, it has been found by experiment that with a jetorifice having a diameter Within the range from three sixty-fourths toone-eighth of an inch, a pressure of sixty pounds per square inch on thespraying liquid supplied to the nozzle, an air blast velocity at thenozzle of approximately ninety miles per hour, and the planes of thesloping ends 24 and 25 of the head 23 disposed to diverge at angles offifty-five degrees in the direction of air flow past the nozzle, thespray particle size will be between 30 and microns.

Since such a wide variation in orifice sizes at the above specifiedconstant pressure would produce a wide variation in volume output ofspraying liquid, it is important to note that the spray particle sizerange remains quite constant throughout such variation. Furtherexperments indicate that best nozzle performance results are obtainedwhen the end faces 24 and 25 of the head divergefrom the direction ofair flow past the nozzle at angles within the range between fifty andseventy degrees.

The threaded hole 28 in the tubular head portion 23 to receive the jetfitting 18 is so located that the longer side of the head portion willbe on the downstream side of the nozzle. Therefore, when, as shown inFig. 4, a support and liquid supply tube 10a and jet fitting 18a aremounted in a tubular air tunnel 29 with their common axis extending inthe direction of flow of the air stream, the jet fitting will be screwedinto a threaded hole provided therefor in the short or upstream side ofthe head 23a. This disposes the sloping end faces 24a and 25a of thehead 23a at divergent angles to the direction of air flow past thenozzle.

All threads in the form of the invention illustrated are of the taperedor iron pipe type so that the parts can be drawn down into frictionallysecured relation to each other, and still be capable of being removedand replaced as required.

Briefly, the operation of the device is as follows: The shear nozzle ismounted with the longer side of the head 23 on the downstream side ofthe air blast on a fitting 18 having an orifice 22 of predetermined sizetherein. The volume of liquid supplied by the nozzle can be variedeither by changing the orifice size, or by varying the pressure'on theliquid supplied to the nozzles. Usual air blast generating means, notshown, such as a suitable motor driven blower or fan, is then placed inoperation to discharge a high velocity air blast past the nozzle,

n the sp ying l q id. is discharged unde prede ermined pressure into thehead 23 through the jet orifice 22.

The jet of liquid discharged through the orifice 22 r k the h d oppos tthe f t ne 13, he the dr vi g force of the jet causes the liquid tospreadradially in all directions from the point of impact as a center wih a force much greater than the force of gravity, with the result thatthe liquid is spread over the inner wall of the head 23, and is causedto flow toward the diagonally diverging head ends 24 and 25. Here theair blast shears oil. particles of liquid both on the short or upstreamedge portions 241) and 25b of the sloping ends of the head, and also onthe longer downstream edges 24c and 25c thereof. The diagonal slope ofthe ends of the head 23 provides an offsetting of the upstream anddownstream edges thereof to expose both of them to the shearing actionof the air blast. It also provides a sharpened or chisel-like edge onthe downstream sides of both of said edge portions. This sharpened,chisel-like edge structure insures that the film of liquid flowingthereto will be; sheared oli in droplets of relatively uniform size.

Since the intermediate edge portions 24:] and 25d of. the nozzle endsare curved to extend generally longi-. tudinally of the direction of airflow past the nozzle, little or no shearing action occurs along theseedge portions, but the liquid flowing thereto will mostly be blown bythe air blast around toward the projecting downstream edges Zdc and 25c,where such liquids will be sheared or taken oi in droplets by the actionof the air blast flowing across these transversely extending sharpenededge portions. It is obvious that since the longer downstream edges 24cand 25c of the head project out into unobstructed portions of the airstream, the most effective air flow will be across such projectingdownstream edges, and therefore the normal flow of most of the liquidtoward this downstream edge is a fortunate but inherent characteristicof the nozzle. This flow of a major portion of the liquid toward thedownstream edges of the head, is not materially affected by the positionof the nozzle with respect to the vertical, since the previouslymentioned spreading action of jet impact plus the strong eddy currentswithin the head affect the flow of the liquid film toward the ends ofthe head much more than does gravity. Therefore, the liquid is shearedelf in a T618". tively uniform manner from all of the nozzles regardlessof whether they are upright, on end, or inverted.

The fact that the spray particle size range remains relatively constantthroughout a considerable range of volume output of liquid as set forthpreviously herein, is

extremely important in a nozzle of this character, since it allowsv theoperator considerable latitude in his selection of spray density whileretaining optimum particle size. This avoids the creation of anexcessive amount of either excessively small droplets which tend todrift away or evaporate, or excessively large droplets which causewasteful run-off.

While in the illustrated embodiment of the invention the nozzle head 23is of circular cross sectional shape and the jet fitting 18 is separabletherefrom, it will be obvious that the head can be of other crosssectional shapes, as mentioned previously herein, and that the body ofthe jet fitting can be formed, for example by well known die castingmethods, as a part of the head. Also, while illustrated as being mountedin the air stream of ordinary types of Sprayers, the nozzle is capableof use in any air stream of suitable velocity, for example on anairplane for aerial spraying of crops or orchards.

It will be understood therefore that these and other changes andmodifications in the details of the nozzle and its mounting arrangementmay be made without departing from the spirit and scope of the inventionas set forth in the appended claims,

Having thus, described the invention, what I claim new and desire toprotect by Letters Patent is as foliows:

1. A shear nozzle comprising a conduit having an open end thereof slopedat an acute angle relative to its axis, means for directing a highvelocity air stream past said open end, and means for supplying liquid,in suficient quantity to form a film, to the interior wall of saidconduit for flow along the wall to the marginal edge portion of the openend of the conduit for shear takefl? y a d ai s r am- 2. A shear nozzlecomprising a tubular head having an end thereof; sloped at a divergentangle relative to a transverse plane normal to the tubular axis of saidhead, means directing an air stream past said head and a liquid pp y pases-e penin hr ugh rific in the inicrior of said head to dis hargeliquid interiorly of said head, for spreading in; the term; of a filmover the interior thereof to said sloping end forshear take-offby saidairstream.

iq i dis ibutin device c mpr si means for creating a high velocity airstream, a support having a liquid supply passage extending lengthwisetherein and adapted to be connected at one end thereof to a liquidsupply pipe, a short length of tubing: mounted on the other end of saidsupport to he within the air stream with the tubing axis disposed atright angles to the direction of air flow past the tubing, the ends otthe tub ingbeing open, and disposed in planes diagonal to the tubingaxis which m an. an le d v r e t in t direction of air flow past thetubing, and an opening from the supply passage into the interior of thetubing through an orifice positioned to direct the liquid dischargedtherethrough toward the interior of the tubing wall for spreadingthereover in the formv of a film flowing to the diagonal tubing ends,there to, be sheared oil by the passing air stream.

4. A spray device comprising means for directing a high velocity airstream in a predetermined direction a portion of tubing having a slopingopen end and mounted to extend transversely to the direction of flow ofsaid air stream with the sloping open end of the tubing being directlyexposed to. said air stream, and means for supplying a film of water tothe edge of the tubing surrounding the sloping open end of said tubingto be sheared off" in droplets by the passing air stream.

References Cited in the file of this patent UNITED STATES PATENTS

